Improved circuit-closer



' BIGGAR & 11000.;

I Fi e Telegraph. No. 79,894. v Patented July 14, 1868.;

N PEIERS, PNDTO-UTNOGRAPHR WASMINGTON, 01C.

UNITED STATES PATENT OFFICE.

WILLIAM J BIGGAR AND JOHN G. BLOOD, OF OONNEAUT, OHIO.

IMPROVED CIRCUIT-CLOSER.

Specification forming part of Letters Patent No. 79,894, dated July 14, 1868.

To all whom it may concern:

Be it known that we, WILLIAM J. BIGGAR and JOHN G. BLOOD, of Conueaut, in the county of Ashtabula and State of Qhio, have invented a new and useful Improvement in Burglar Fire-Alarm; and we do hereby declare that the following is afull, clear, and exact description thereof, which will enable thoseskilled in the art to make and use the same, reference being bad to the accompanying drawin g, forming part of this specification, in which the drawing represents our improvement in a burglar fire-alarm. v

This invention relates to a new anduseful circuit-breaker for a fire-alarm, designed to be connected with the apparatus of a magnetic burglar-alarm for which Letters Patent have been applied for by- William J. Biggar, John 0. Blood, and D. M. Griswold, in connection with a device for breaking the electromagnetic circuit by the entrance of a burglar through a door or window.

Our improved device for a circuit-breaker is operated on by the heat of a fire that may occur in a room where it is placed, and thus give timely alarm through the agency of the magnetic signal, as hereinafter described.

A strip of wood, A, is provided with a circuit-breaker operated by the heat of an accidental fire which may occur in the room where it is placed.

Theiusulated wires a, a are connected with the poles of a magnetic battery having a signal-alarm attached to it, and form an electromagnetic circuit through the circuit-breaker, one wire, a, being secured to the metal pin or post b, and the other, a, to the post b, set on the wooden base A. The two posts b b are connected by a lever, c, that is pivoted at one end on the post 12, and by means of a coilspring, d, bears at the other end against the post I), to form the circuit-connection between the wires a. a.

Running lengthwise with the base-board A are two straightstrips of metal, m a, secured to the board at their ends and lying side by side, the inside strip, on, being made of brass and the outside strip, n, of iron, made a little thinner than the brass strip. A sliding pin or bolt, 0, is fitted to lie eudwise between the middle of the strip mand the lever c, touching both.

As the powers of expansion of the two metals brass and iron, under the influence of heat, are difl'erent in degree, and brass expands more rapidly than iron, it will be seen that with this arrangement of the metal stripsmn, it they are exposed to an unusual degree of heat, they will form a curve, by their expansion, with the brass strip on the convex side. The expansion of the two metals, therefore, which would be produced by the heat of a fire to which they might be exposed would push up the bolt 6 against the lever c and lift it away from the post 1), whereby the circuit of the magnetic current of thewires a a would be broken and the alarm of fire would be sounded by the signal connected with the battery.

This fire-alarm device would be fastened near the ceiling of-a room, where theheatofa fire acts quickly, and be placed in any number of rooms of a building connected with the same set of insulated wires connected with the battery and alarm apparatus, and thus secure protection against accidental fire.

Having described our invention, we claim as new and desire to secure by Letters Patent The combination of the board A, the brass and iron strips m n, the sliding bolt 0, the spring-lever c, and the posts b b with the insulated wires a (1, arranged and operating substantially as and for the purpose herein described.

WILLIAM J. BIGGAR. JOHN C. BLOOD. Witnesses:

G. R. GODDARD, O. O. COUGHLAN. 

